Lecture Notes: Simplifying Concave vs. Convex Rules

Introduction

• Speaker: Scott Solomon from Board Preppers
• Topic: Simplifying concave and convex rules for board exams
• Objective: Prevent confusion in distinguishing concave vs. convex surfaces during exams

Key Concepts

1. Definitions:

   • Concave Surface: Curved inward
   • Convex Surface: Curved outward

2. Examples:

   • Glenoid Fossa: Concave
   • Head of Humerus: Convex

Upper vs. Lower Extremity

• Both extremities follow the same concave-convex principles.
• Focus on the upper extremity for explanation:
  • Shoulder Joint:
    • Glenoid Fossa (Concave)
    • Head of Humerus (Convex)
  • Elbow Joint:
    • Distal Humerus (Convex)
    • Proximal Forearm (Concave)
  • Wrist Joint:
    • Styloid Process of Radius/Ulna (Concave)
    • Carpal Bones (Convex)

Pattern Explanation

• Use letters to denote surfaces:
  • A (Concave) and **X (Convex)"
  • Pattern: A X X A A X (for both upper and lower extremities)**

Open Chain vs. Closed Chain Activities

• Open Chain:

  • Proximal end is fixed, distal end moves.
  • Moving bone dictates the rule (e.g., distal bone).

• Closed Chain:

  • Distal end is fixed, proximal end moves.
  • Moving bone rules (e.g., proximal bone).

Application of Rules

• Shoulder/Hip:
  • Open Chain: Convex
  • Closed Chain: Concave
• Elbow/Knee:
  • Open Chain: Concave
  • Closed Chain: Convex
• Wrist/Ankle:
  • Open Chain: Convex
  • Closed Chain: Concave

Study Tip

• Memorize the pattern A X X A A X
• Draw on whiteboards for quick reference.
• Practice applying rules to ensure clarity during exams.

Conclusion

• Speaker's Message: Thanks for tuning in. More instructional content coming soon.